The more strings you have for your bow, the better off you are. I went for years using only a map (and occasionally a compass). They are fundamental, and should be mastered by everyone who aspires to competence. GPS, used properly, is a great tool. I use one regularly when cycling or hiking because it gives me unparalleled accuracy and info on distance traveled, speed, average speed, etc. A nifty tool.

And yes, it is definitely the right tool when you leave your while vehicle and disappear into the fog.